Question: In triangle $PQR,$ $\angle Q = 30^\circ,$ $\angle R = 105^\circ,$ and $PR = 4 \sqrt{2}.$  Find $QR.$
We have that $\angle P = 180^\circ - 30^\circ - 105^\circ = 45^\circ.$  Then by the Law of Sines,
\[\frac{QR}{\sin P} = \frac{PR}{\sin Q}.\]Hence,
\[QR = PR \cdot \frac{\sin P}{\sin Q} = 4 \sqrt{2} \cdot \frac{\sin 45^\circ}{\sin 30^\circ} = \boxed{8}.\]